| 20103592 |
Sun X, Jones WT, Harvey D, Edwards PJ, Pascal SM, Kirk C, Considine T, Sheerin DJ, Rakonjac J, Oldfield CJ, Xue B, Dunker AK, Uversky VN: N-terminal domains of della proteins are intrinsically unstructured proteins in the absence of interaction with gid1 ga receptors. J Biol Chem. 2010 Jan 26.
The plant growth-repressing DELLA proteins (DELLAs) are known to represent a convergence point in integration of multiple developmental and environmental signals in planta, one of which is hormone gibberellic acid (GA). Binding of the liganded GA receptor (GID1/GA) to the N-terminal domain of DELLAs is required for GA-induced degradation of DELLAs via the ubiquitin-proteasome pathway, thus de-repressing of plant growth. However, the conformational changes of DELLAs upon binding to GID1/GA, which are the key to understand the precise mechanism of GID1/GA-mediated degradation of DELLAs, remain unclear. Using biophysical, biochemical and bioinformatics approaches we demonstrated for the first time that the unbound N-terminal domains of DELLAs are intrinsically unstructured proteins (IUPs) under physiological conditions. Within the intrinsically disordered N-terminal domain of DELLAs, we have identified several Molecular Recognition Features (MoRFs), sequences known to undergo disorder-to-order transitions upon binding to interacting proteins in IUPs. In accordance with the MoRFs analyses, we have observed the binding-induced folding of N-terminal domains of DELLAs upon interaction with AtGID1/GA. Our results also indicate that DELLA proteins can be divided into two subgroups in terms of their molecular compactness and their interactions with monoclonal antibodies. |
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